Hilo

Today: Mostly sunny with scattered showers. Haze. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to around 53 at 4000 feet. Southeast winds up to 10 mph shifting to the southwest after midnight. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs around 83 near the shore to 69 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Haze in the afternoon. Highs 79 to 84 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy in the evening then becoming mostly clear. Isolated showers. Lows 67 to 73 near the shore to around 54 near 5000 feet. Northeast winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Thursday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 81 to 86 near the shore to around 69 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 40 percent.

Waimea

Today: Mostly sunny with isolated showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to 55 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs around 81 near the shore to 69 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny with isolated showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to 55 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs around 81 near the shore to 69 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs around 83 near the shore to around 72 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 68 near the shore to around 52 near 5000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Breezy. Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to around 73 near 5000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Puna

Today: Mostly sunny with scattered showers. Haze. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to around 53 at 4000 feet. Southeast winds up to 10 mph shifting to the southwest after midnight. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs around 83 near the shore to 69 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the afternoon. Highs around 84 near the shore to 67 to 73 above 4000 feet. Light winds becoming northwest around 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 68 to 74 near the shore to 49 to 56 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Thursday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to 69 to 75 above 4000 feet. North winds up to 10 mph. Chance of rain 40 percent.

Detailed Forecast

Update

Halemaumau Crater on the Kilauea Volcano Summit erupted at 4:44 AM HST this morning. This eruption was observed on infrared satellite imagery. Radar indicates winds will likely cause any ash emissions to drift towards the west-southwest direction this morning. A Special Weather Statement has been issued to cover the possibility of very light ashfall. We have also added haze (vog) to the forecast through this afternoon for the Puna, Kau and South Kona Districts on the Big Island.

Synopsis

A weak surface ridge north-northeast of the state will maintain light to moderate trade winds, with local sea and land breezes developing across sheltered areas of the islands into Thursday. Trade showers will favor windward facing slopes during the night and early morning hours, with showers forming over some interior and leeward sections each afternoon. Locally breezy trade winds will likely return from late Thursday and Friday into early next week. This will bring a return to a more typical trade wind weather pattern with brief showers focused mainly over windward areas by this weekend.

Discussion

The southern end of a weak surface front, which appears to be about 300 miles north of Lihue, is moving slowly toward the east- southeast. In addition, the western end of a weak surface ridge is about 300 miles north-northeast of Honolulu. The close proximity of these features to the state is keeping the pressure gradient relatively weak over the region early this morning. This is producing light to locally moderate trade winds across the island chain. The background flow have been light enough to allow local land breezes to become established over leeward and interior sections of each island overnight. The trade winds will continue to transport brief light showers into windward facing sections of some of the islands this morning. However, rainfall totals are expected to be meager over most areas due to the rather dry and stable atmospheric conditions.
The forecast guidance indicates the tail end of the front will continue to move slowly toward the east-southeast, and gradually dissipate through Thursday. The weak surface ridge will also remain north-northeast of the region, so the light to moderate trade winds will persist. In addition, dry and stable atmospheric conditions will likely continue. Therefore, expect the pattern of local afternoon sea breezes, followed by nighttime land breezes to dominate the weather pattern into Thursday. This scenario will keep showers focused over windward sections during the nights and early mornings. Then clouds and showers will develop over the interior and leeward sections of the islands each afternoon as the sea breezes become established, followed by clearing over these same areas as land breezes develop at night.
Once the front dissipates around late Thursday, a new surface high will likely build far northwest of the area. This will cause the pressure gradient to tighten across the islands, which will result in the trade winds strengthening from Thursday night into early next week. This will lead to a rather typical trade wind weather pattern with windward and mauka showers. The trade winds may be strong enough to allow a few showers to be transported to leeward sections of some of the smaller islands, especially at night. In addition, expect clouds and spotty showers to develop each afternoon over the upslope sections of the leeward Big Island.

Aviation

A frontal system passing to the north of the state will help keep the pressure gradient weak and generate mainly light trade winds across the islands through the forecast period. Thus, isolated to scattered showers will be mainly confined to windward locations this morning. Brief MVFR conditions may accompany any of the more robust showers.
By early this afternoon, sea breeze development could help initiate scattered showers along the leeward mountains and coasts.
No AIRMETs are currently in effect.

Marine

A cold front passing far north of the region will weaken the high pressure ridge far north of the state. Trade winds will remain in the light to fresh range today, and then strengthen from Thursday onward as high pressure builds back into the region.
Small surf will continue along south facing shores as a mix of background long period south and southwest (170-220 degrees) swells continue into next week.
Surf along exposed north and west facing shores will see an out of season west-northwest (300-310 degrees) swell, from former northwest Pacific Tropical Cyclone Mawar, will fill in later today. This swell will peak on Thursday, hold through Friday and then slowly subside through the weekend.
Surf along east facing shores will remain small into Thursday due to lower trade winds. A slight increasing trend will start Thursday night as trade winds strengthen.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov